Nadia is 5 times as old as Umaima and is also 8 years older than Umaima. How old is Nadia?
Explanation: We can use the given information to write down two equations that describe the ages of Nadia and Umaima. Let Nadia's current age be $n$ and Umaima's current age be $u$ $n = 5u$ $n = u + 8$ Now we have two independent equations, and we can solve for our two unknowns. One way to solve for $n$ is to solve the second equation for $u$ and substitute that value into the first equation. Solving our second equation for $u$ , we get: $u = n - 8$ . Substituting this into our first equation, we get the equation: $n = 5$ $(n - 8)$ which combines the information about $n$ from both of our original equations. Simplifying the right side of this equation, we get: $n = 5n - 40$ Solving for $n$ , we get: $4 n = 40$ $n = 10$.